Chain tensioners in engines are used to control the power transmission chains as the chain travels around a plurality of sprockets. The slack of the chain varies as the temperature in an engine increases and as the chain wears. When a chain wears, the chain elongates and the slack in the chain increases. The increase in slack may cause noise, slippage, or tooth jumping between the chain and the sprocket teeth. If the increase of the slack of the chain is not taken up, by a tensioner for example, in an engine with a chain driven camshaft, the engine may be damaged because the camshaft timing is misaligned by several degrees due to slippage or tooth jumping.
Various configurations for closed loop chain tensioner systems are known from U.S. Pat. No. 7,476,168: U.S. Pat. No. 7,429,226; U.S. Pat. No 6,955,621; U.S. Pat. No. 6,322,470; U.S. Pat. No. 5,951,423; U.S. Pat. No. 5,489,056; U.S. Pat. No. 3,856,101; U.S. Pat. No. 2,210,276; French Patent No. 2,832,358; and Japanese Patent No. 2002-089,636. While each of these configurations is satisfactory for performing its intended function, several of these configurations provide restricted space and location sites for the tensioner driver. It would be desirable to provide a tensioning system that overcomes these limitations, and that provides additional benefits as described below.